Dirt Logic 2.5 Resi Coilovers. From our desert racing experience the Dirt Logic 2.5 has been developed for exceptional performance in a variety of Coilover applications. The Dirt Logic 2.5 will provide incredible dampening capacity for aggressive offroad driving. Features: 2.5in OD Stainless Steel Body. 2.25in OD Billet Aluminum Piston. 7/8in NitroSteel Black Piston Rod. Cold Wound Coil Springs. Adjustable Coilover Construction. 5/8in Spherical Ball Mounting Ends. 2.50in OD Aluminum Reservoir w/-8 Stainless Steel O-ring Hose. Extended Length - E23.80. Collasped Length - C19.70. Stroke Length - S4.10 . Top Mount - TP. Bottom Mount - OSBP.